batman-adv: Delete unnecessary checks before the function call "kfree_skb"

The kfree_skb() function tests whether its argument is NULL and then
returns immediately. Thus the test around the calls is not needed.

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Antonio Quartulli <a@unstable.cc>
diff --git a/net/batman-adv/send.c b/net/batman-adv/send.c
index f664324..782fa33 100644
--- a/net/batman-adv/send.c
+++ b/net/batman-adv/send.c
@@ -407,8 +407,7 @@
 
 static void batadv_forw_packet_free(struct batadv_forw_packet *forw_packet)
 {
-	if (forw_packet->skb)
-		kfree_skb(forw_packet->skb);
+	kfree_skb(forw_packet->skb);
 	if (forw_packet->if_incoming)
 		batadv_hardif_free_ref(forw_packet->if_incoming);
 	if (forw_packet->if_outgoing)